1 // SPDX-License-Identifier: GPL-2.0
6 #include <linux/kernel.h>
7 #include <linux/zalloc.h>
11 #include "thread-stack.h"
13 #include "namespaces.h"
18 #include "callchain.h"
20 #include <api/fs/fs.h>
22 int thread__init_maps(struct thread *thread, struct machine *machine)
24 pid_t pid = thread->pid_;
26 if (pid == thread->tid || pid == -1) {
27 thread->maps = maps__new(machine);
29 struct thread *leader = __machine__findnew_thread(machine, pid, pid);
31 thread->maps = maps__get(leader->maps);
36 return thread->maps ? 0 : -1;
39 struct thread *thread__new(pid_t pid, pid_t tid)
43 struct thread *thread = zalloc(sizeof(*thread));
50 INIT_LIST_HEAD(&thread->namespaces_list);
51 INIT_LIST_HEAD(&thread->comm_list);
52 init_rwsem(&thread->namespaces_lock);
53 init_rwsem(&thread->comm_lock);
55 comm_str = malloc(32);
59 snprintf(comm_str, 32, ":%d", tid);
60 comm = comm__new(comm_str, 0, false);
65 list_add(&comm->list, &thread->comm_list);
66 refcount_set(&thread->refcnt, 1);
67 RB_CLEAR_NODE(&thread->rb_node);
68 /* Thread holds first ref to nsdata. */
69 thread->nsinfo = nsinfo__new(pid);
70 srccode_state_init(&thread->srccode_state);
80 void thread__delete(struct thread *thread)
82 struct namespaces *namespaces, *tmp_namespaces;
83 struct comm *comm, *tmp_comm;
85 BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
87 thread_stack__free(thread);
90 maps__put(thread->maps);
93 down_write(&thread->namespaces_lock);
94 list_for_each_entry_safe(namespaces, tmp_namespaces,
95 &thread->namespaces_list, list) {
96 list_del_init(&namespaces->list);
97 namespaces__free(namespaces);
99 up_write(&thread->namespaces_lock);
101 down_write(&thread->comm_lock);
102 list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
103 list_del_init(&comm->list);
106 up_write(&thread->comm_lock);
108 nsinfo__zput(thread->nsinfo);
109 srccode_state_free(&thread->srccode_state);
111 exit_rwsem(&thread->namespaces_lock);
112 exit_rwsem(&thread->comm_lock);
116 struct thread *thread__get(struct thread *thread)
119 refcount_inc(&thread->refcnt);
123 void thread__put(struct thread *thread)
125 if (thread && refcount_dec_and_test(&thread->refcnt)) {
127 * Remove it from the dead threads list, as last reference is
128 * gone, if it is in a dead threads list.
130 * We may not be there anymore if say, the machine where it was
131 * stored was already deleted, so we already removed it from
132 * the dead threads and some other piece of code still keeps a
135 * This is what 'perf sched' does and finally drops it in
136 * perf_sched__lat(), where it calls perf_sched__read_events(),
137 * that processes the events by creating a session and deleting
138 * it, which ends up destroying the list heads for the dead
139 * threads, but before it does that it removes all threads from
140 * it using list_del_init().
142 * So we need to check here if it is in a dead threads list and
143 * if so, remove it before finally deleting the thread, to avoid
144 * an use after free situation.
146 if (!list_empty(&thread->node))
147 list_del_init(&thread->node);
148 thread__delete(thread);
152 static struct namespaces *__thread__namespaces(const struct thread *thread)
154 if (list_empty(&thread->namespaces_list))
157 return list_first_entry(&thread->namespaces_list, struct namespaces, list);
160 struct namespaces *thread__namespaces(struct thread *thread)
162 struct namespaces *ns;
164 down_read(&thread->namespaces_lock);
165 ns = __thread__namespaces(thread);
166 up_read(&thread->namespaces_lock);
171 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
172 struct perf_record_namespaces *event)
174 struct namespaces *new, *curr = __thread__namespaces(thread);
176 new = namespaces__new(event);
180 list_add(&new->list, &thread->namespaces_list);
182 if (timestamp && curr) {
184 * setns syscall must have changed few or all the namespaces
185 * of this thread. Update end time for the namespaces
188 curr = list_next_entry(new, list);
189 curr->end_time = timestamp;
195 int thread__set_namespaces(struct thread *thread, u64 timestamp,
196 struct perf_record_namespaces *event)
200 down_write(&thread->namespaces_lock);
201 ret = __thread__set_namespaces(thread, timestamp, event);
202 up_write(&thread->namespaces_lock);
206 struct comm *thread__comm(const struct thread *thread)
208 if (list_empty(&thread->comm_list))
211 return list_first_entry(&thread->comm_list, struct comm, list);
214 struct comm *thread__exec_comm(const struct thread *thread)
216 struct comm *comm, *last = NULL, *second_last = NULL;
218 list_for_each_entry(comm, &thread->comm_list, list) {
226 * 'last' with no start time might be the parent's comm of a synthesized
227 * thread (created by processing a synthesized fork event). For a main
228 * thread, that is very probably wrong. Prefer a later comm to avoid
231 if (second_last && !last->start && thread->pid_ == thread->tid)
237 static int ____thread__set_comm(struct thread *thread, const char *str,
238 u64 timestamp, bool exec)
240 struct comm *new, *curr = thread__comm(thread);
242 /* Override the default :tid entry */
243 if (!thread->comm_set) {
244 int err = comm__override(curr, str, timestamp, exec);
248 new = comm__new(str, timestamp, exec);
251 list_add(&new->list, &thread->comm_list);
254 unwind__flush_access(thread->maps);
257 thread->comm_set = true;
262 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
267 down_write(&thread->comm_lock);
268 ret = ____thread__set_comm(thread, str, timestamp, exec);
269 up_write(&thread->comm_lock);
273 int thread__set_comm_from_proc(struct thread *thread)
280 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
281 thread->pid_, thread->tid) >= (int)sizeof(path)) &&
282 procfs__read_str(path, &comm, &sz) == 0) {
284 err = thread__set_comm(thread, comm, 0);
290 static const char *__thread__comm_str(const struct thread *thread)
292 const struct comm *comm = thread__comm(thread);
297 return comm__str(comm);
300 const char *thread__comm_str(struct thread *thread)
304 down_read(&thread->comm_lock);
305 str = __thread__comm_str(thread);
306 up_read(&thread->comm_lock);
311 /* CHECKME: it should probably better return the max comm len from its comm list */
312 int thread__comm_len(struct thread *thread)
314 if (!thread->comm_len) {
315 const char *comm = thread__comm_str(thread);
318 thread->comm_len = strlen(comm);
321 return thread->comm_len;
324 size_t thread__fprintf(struct thread *thread, FILE *fp)
326 return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
327 maps__fprintf(thread->maps, fp);
330 int thread__insert_map(struct thread *thread, struct map *map)
334 ret = unwind__prepare_access(thread->maps, map, NULL);
338 maps__fixup_overlappings(thread->maps, map, stderr);
339 maps__insert(thread->maps, map);
344 static int __thread__prepare_access(struct thread *thread)
346 bool initialized = false;
348 struct maps *maps = thread->maps;
351 down_read(&maps->lock);
353 maps__for_each_entry(maps, map) {
354 err = unwind__prepare_access(thread->maps, map, &initialized);
355 if (err || initialized)
359 up_read(&maps->lock);
364 static int thread__prepare_access(struct thread *thread)
368 if (dwarf_callchain_users)
369 err = __thread__prepare_access(thread);
374 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
376 /* This is new thread, we share map groups for process. */
377 if (thread->pid_ == parent->pid_)
378 return thread__prepare_access(thread);
380 if (thread->maps == parent->maps) {
381 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
382 thread->pid_, thread->tid, parent->pid_, parent->tid);
385 /* But this one is new process, copy maps. */
386 return do_maps_clone ? maps__clone(thread, parent->maps) : 0;
389 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
391 if (parent->comm_set) {
392 const char *comm = thread__comm_str(parent);
396 err = thread__set_comm(thread, comm, timestamp);
401 thread->ppid = parent->tid;
402 return thread__clone_maps(thread, parent, do_maps_clone);
405 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
406 struct addr_location *al)
409 const u8 cpumodes[] = {
410 PERF_RECORD_MISC_USER,
411 PERF_RECORD_MISC_KERNEL,
412 PERF_RECORD_MISC_GUEST_USER,
413 PERF_RECORD_MISC_GUEST_KERNEL
416 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
417 thread__find_symbol(thread, cpumodes[i], addr, al);
423 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
425 if (thread->pid_ == thread->tid)
426 return thread__get(thread);
428 if (thread->pid_ == -1)
431 return machine__find_thread(machine, thread->pid_, thread->pid_);
434 int thread__memcpy(struct thread *thread, struct machine *machine,
435 void *buf, u64 ip, int len, bool *is64bit)
437 u8 cpumode = PERF_RECORD_MISC_USER;
438 struct addr_location al;
441 if (machine__kernel_ip(machine, ip))
442 cpumode = PERF_RECORD_MISC_KERNEL;
444 if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso ||
445 al.map->dso->data.status == DSO_DATA_STATUS_ERROR ||
446 map__load(al.map) < 0)
449 offset = al.map->map_ip(al.map, ip);
451 *is64bit = al.map->dso->is_64_bit;
453 return dso__data_read_offset(al.map->dso, machine, offset, buf, len);